Patient operated invalid bed



g- 5, 1952 A. L. BURKHART 2,605,481

PATIENT OPERATED INVALID BED Filed May 18, 1946 4 Sheets-Sheet 1INVENTOE Aug. 5, 1952 A. BURKHART PATIENT OPERATED INVALID BED Filed May18, 1946 4 Sheets-Sheet 5 7 /111/1////A| I i INVENTOR. fire/liq layer;.Bqrk/Ian Patented Aug. 5, 1952 UNITED STATES PATENT OFFICE 6 Claims.

Beds such as are used in hospitals, sanitariums, and in the home forcertain purposes, comprise a structure in which the spring of the bed isformed in a plural number of sections which are hingedly joinedtogether, and which are adapted to be raised and lowered by means of ahand operated leverage system attached to each of the movable springsections. This arrangement is had to enable the patient to be raised tositting position for greater comfort and relaxation, likewise, thespring sections which support the lower limbs or legs may also be raisedfor comfort and relaxation. Bed springs of the type herein contemplatedare movable from a horizontal position to a maximum elevation and ofcourse may be adjusted to any one of a variable number of intermediatepositions.

If a bed-fast patient or other invalid desires to be raised towardsitting position for better breathing comfort, reading or mererelaxation from lying flat upon the back, it is necessary to call anurse or other attendant to manually operate the crank driven mechanicalaccessories to raise the movable elements of the bed to the pointdesired by the patient. Due to the many duties imposed upon a nurse in ahospital, each extra call for such service as adjusting a bed to suit apatients desire, merely adds to an overtaxed days labor, and because ofmany other necessary duties, frequently delays a requested bedadjustment to a point of exasperation by the patient who cannot helphimself.

Experience has shown that many bed-ridden patients become restive, andas a result thereof make many calls for bed adjustments which follow oneanother in relatively quick sequence whereb hardship is worked upon theattendant,

or disappointment and fretting by the patient if their call is notquickly responded to.

In contra-distinction to the afore-described and established practice, Ihave devised a patient operated power means to raise and lower movablesegments of the patients own bed whereby his every whim may be met withrespect thereto, and this feature constitutes the prime object of theinvention.

Another object of the invention is to provide an extremely flexiblepower means, such as is af-. forded by electrical energy, to adjustablyvary the point of elevation of the movable sections of a hospital bed,wherein the patient operated controls are in a low voltage circuitadapted to open and close relays in a power circuit servicing the motorsemployed in raising and lowering the bed, thus ensuring a maximum ofsafety for the patient with respect thereto.

A further object of the invention resides in the provision of means incombination with electrical power means to actuate the movableelements-of a hospital type of bed, whereby upon failure of any of thecomponent parts of the last stated power means, manual means may beemployed to actuate the several movable elements of the bed withoutinterference by the component ele-. ments of the electrical power train.

A still further object of the invention is to provide electrical powermeans to actuate the several movable sections of a hospital type of bedin precise increments of total available lifting freeway, and whereincomplete safety of the patient is positively assured with respect toelectrical energy, together with such a degree of ease and flexibilityof control of movement that any person competent enough to be placedunfettered in such a bed, is able to control the movement thereof withcomplete and absolute assurance.

A feature of the invention resides in the inclusion of limit switcheswithin the electrical circuit, whereby upon attainment of extremepredetermined bed positions, electrical energy is cut-01f from thecontrol circuit in use, thereby preventing power application beyond thepredetermined limits, whereby damage to the power train and bedstructure, as well as upset of the patient is impossible.

A further object of the present invention is to provide a power drive,together with controls therefore, which is adapted to be installed uponexisting hospital type bed structures with a minimum degree ofnecessitated alteration therein.

Other objects, features and advantages of the invention may appear inthe following specification, the detailed drawing, and the sub-joinedclaims.

In the drawing: Q

Figure l is a view partially in section showing a hospital type of bedin which certain of the spring sections thereof are movable withinpredetermined limits in response to electrical power impulse operatingthrough an intermediate leverage system interposed between the movableelements of the bed and functionally operable electric motors.

Figure 2 is a plan view showing or illustrating the construction used inFigure 1.

Figure 3 is a side-elevational View of one of the gear housing unitswith a motor attached.

Figure 4 is a plan view of the structure shown in Figure 3.

Figure 5 is a sectional view showing a fragment of the gear train caseand particularly showing the means used to disconnect the motor and en-3 trained gears from the bed operating shaft to enable manual operationthereof to be had, the coupling is shown in released position for manualoperation by means of an associated hand crank.

Figure 6 is a view partially in section as seen along line 6G, Figureshowing construction of the releasable coupling.

Figure '7 is a transverse sectional view through the gear train case,showing the coupli n power drive position, certain of the elementsthereof, including the motor being shown in top plan.

Figure 8 is a view similar to Figure 7, excepting that here the whole ofthe assembly, excepting the motor, is shown in section.

Figure 9 is a view showing, in diagram, the electric circuit used toservice and control the motors used in operating the bed.

Figure 10 is a view showing limit switches attached to bed structure.

In the drawing the reference character 23 indicates a so-called hospitaltype of bed, comprising a rigid angle iron frame 22 supported upon posts24, and in which the frame 22 is adapted to support a plural number ofbed-spring sections 23 which are hingedly joined together whereby theymay be raised from their normal horizontal position to a maximumelevation and including any intermediate position.

The present invention is not primarily concerned with the system ofleverage used to raise and lower the bed-spring sections, but ratherwith a controlled power means adapted to manipulate the bed-springsection to and from an elevated position, however, in showing andapplying the use of power for this purpose, one form of leverage adaptedto this use will be described.

As shown in Figures 1 and 2, the frame 22 is adapted to support abearing 28 upon each of the longitudinal rails thereof, to journal atransversely disposed shaft 30, upon which a bellcrank 32 is operablypositioned. The greater of the legs thereof, that is, leg 34 is swivellyfitted with a link 36, the outer end of which is hingedly positionedupon a pin which extends through spaced and parallel lugs located uponand downwardly extending from the structural element 42 of thebed-spring section 44, while the leg 35 of the bell-crank is hingedlyconnected with a threaded shaft 48, which in turn is threadedly engagedwith a rotatable nut 43 formed as an integral portion of the shaft 50,which in its extension toward the foot A of the bed 20, is provided witha thrust bearing 54, and from which latter point the shaft extends toand is rotated by a power means to be hereinafter described.

Of the remaining bed-spring sections, section 50 is immovable withrespect to the frame 22, while the section 58 is hingedly joined to thestationary section 53 in the same manner that the section 44 is hingedlyjoined thereto, while the section 60 is hingedly joined to the movablesection 53. The free end of the section 63 is provided with rollers 62which carry the end of the section 60 and any weight imposed thereonwhen the sections 58 and 30 are raised to or toward the dotted lineposition 58 and 60.

As shown in the drawing, the bed-spring section 58 is provided with alink I0 which is swivelly connected thereto, and with a bell-crank I2mounted upon the transverse rod 14, which in turn i journalled in thebearings I3 secured upon the longitudinal rails I8 of the frame 22, inidentical manner in which the bell-crank 32 and its organization ismounted for functional use. Likewise the leg 18 of the bell-crank i2 ishingedly joined to a threaded shaft 80, the free end of which is inthreaded union with a nut 82 formed as an extension of the shaft 84, andwhich as stated in connection with the shaft 50, is provided with athrust bearing 88 from which the shaft 84 extends to the gear train case93 and from which point the shaft 34 is motor operated as will behereinafter set forth.

The matter just described refers to a hosiptal type of bed and one formof leverage system which is adapted to raise and lower the severalmovable sections thereof without particularity, excepting in so far asnecessary to show an operable structure.

Attention is now directed to Figures 3 to 8 inclusive wherein I show mypreferred power means to operate the shafts 53 and 84.

The power means for shaft 84 includes a motor I03 which is fixedlymounted upon the gear train case by the use of screws I02 or othersuitable means, and is so arranged with respect to case 90 that motorshaft I04 extends therein. A spur gear I05 upon the shaft I04 is intrain with the gear I03 which is fixedly mounted upon a shaft IIOjournalled in the bearings H2 and H2 mounted in the side walls of thecase 90. A gear II4 formed as an element of the gear I08, or as aseparate unit, is medially aligned around the axis of the shaft H0 androtates therewith, and is in train with the gear I I6 which is mountedupon and keyed to a tubular sleeve II8 which extends across the width ofthe case 93 and outwardly therefrom in parallel relationship to thelongitudinal axis of the motor I00.

The gear I I0 is held in alignment with the gear H4 by means of a spacerI20 upon one of the sides thereof, and by means of other spacers I22 andI24, lateral pressure against which is arrested by the side walls 90aand 90b of the gear train case 90.

The tubular sleeve I I3 as previously mentioned extends across the widthof the case 90, and as shown in several of the figures of the drawing,is mounted upon a driven shaft [26, the end B of which extends to thethrust bearing 88, while the end C thereof is adapted to receive a handoperated crank I28 upon failure of any of the component elements of thepower drive.

The shaft I26 at a point outwardly of the cover plate or side 9012 isfitted with a collar I30 which is suitably fixed in place upon the shaftby such means as a tapered pin I32, while in face contact with thecollar I30, but upon the terminal portion of the sleeve I I8, I place aflanged collar I34 which is keyed to the sleeve I I8 whereby rotationtherewith may be had, while an open ended tubular housing I36 is held infixed relationship With the flanged collar I34 by means of suitablescrews I30. The outer end of the tubular housing I36 is fitted with anapertured disc I40 held therein by means of suitable screws I42, and theaperture of which is proportioned to slidably move over or upon theshaft I26.

An extensible spring I44 encircles the tubular sleeve H3 and ispositioned between the gear train case 93 and the inner face of theflange of the flanged collar I34, whereby the flanged collar I34 isnormally in pressure contact with the fixed collar I33.

Reference to Figure 6 will show that the face I46 of the collar I30 isformed with a plural number of bosses I48 so located with respect to theshaft I26, the sleeve H8 and the key I35,

that upon rotation of the sleeve and key under power drive, ampleclearance is afforded for unobstructed rotational movement. The bossesI48 have their complement in like shaped recesses I49 formed in theflanged collar I34, and normally the bosses rest within the recesses asshown in Figures 7 and 8, due to the fact that the spring I44 exerts aconstant pressure upon the flanged collar I34, forcing it into facecontact with the collar I30, and concurrently forcing or carrying thetubular housing I36 therewith in the direction of the arrow C until suchmovement under spring pressure is arrested by the immovable collar I30.

The gear train cases 90 are provided with lugs 93 and 95 positioned atone end of the respective cases, and are adapted to receive suitablesupporting means 93 and 95 whereby the gear train cases and attachedmotors I00 and IM are pendently supported from a transversely positionedangle iron 91, the end of which are fixedly secured to the longitudinalrails of the frame 22. In conjunction with the aforementioned supports93 and 95 for the gear cases, the weight of these cases is in partsupported by the drive shafts I26, of which there is one in each gearcase, in their relationship with the thrust bearings 54 and 88, therebyproviding sufficient freedom of movement therein to conform with torqueimposition and alignment with the driven shafts 50 and 84 when underpower impulse.

The preceding description is believed to be conclusive of the essentialfeatures of construction involved in the apparatus used to raise andlower the movable segments of a hospital type of bed for patientaccommodation.

A description of the operation of the aforedescribed apparatus,including the electricalcircuit servicing the same will now be had.

Figure 1 is illustrative of the bed in normal horizontal position asshown in full lines, however, if it is desired to raise the head section44 to an elevated position, it is only necessary to energize the motorIOI whereby the shaft 50 is rotated in a clockwise direction, so thatupon rotation thereof and including the nut 48, the threaded shaft 46 isforced outwardly, rotating or rather rocking the bell-crank 32 upon itsaxis or the shaft 30. This movement raises the arm or leg 34 and thelink 36 intervening between the leg 34 and the movable bed-section 44,forcing the section 44 upwardly toward the dotted line position 44', butmay of course be arrested at any point short of this maximum point ofelevation by de-energizing the motor. During the interval that thesection 44 is being raised, a limit switch I50 remains closed pendingattainment of maximum elevation by the section 44, thereafter thisswitch opens and kills the manually controlled circuit to the relay I 52and opens the power circuit to the operating motor IN, the operation ofwhich circuit will be more fully set forth subsequent to the descriptionof the purely mechanical features of the invention. Opening of the limitswitch I50, stops further movement of the section 44 even though theoperator (patient) fails to open the manually controlled switch I54.Also, upon attainment of any position removed from the horizontal, alimit switch I56 automatically moves to closed position, although at themoment the circuit included therein is dead. This arrangement is had toenable the bed section to be lowered, and when in lowermost position,the then energized circuit through this switch will automatically opento arrest the power drive in thrusting the section 44 further than to ahorizontal position. It will be recognized that stopping the motor atany time the section is intermediate of the upper and lowermostposition, will cause the section to remain in such intermediateposition, for the reason that the whole of the leverage assembly used toraise the bed section is held against backward movement by the thrustbearing 54, accordingly it is only possible to lower the section byreversely rotating the nut 48 and the shaft 50.

Movement of the sections 58 and 60 is identical to movement of thesection 44. The limit switches I58 and I60 are the counterpart of theswitches I50 and I56, being used to control maximum movement of thesections in either extreme direction, and are also actuated byapplication or release of pressure derived from movement of the severalsections of the bed, however, it will be recognized that as shown inFigure 10, these switches are idealistically arranged for the sake ofclarity of illustration, and that as a matter of fact they may beactuated by the threaded shafts 46 and 80, or other suitable means whichaccurately and unfailingly indicate by relative movement when the bedsections 44, 58 and 60 have attained the limit of their predeterminedmovement.

Upon failure of the electrical circuit servicing the motors or the motorcontrols, the several bed sections may be raised and lowered by manualoperation of the crank I28,

Manual operation is had by sliding the crank I28 over the free end C ofthe shaft I26 with the pin I26 in the slot I26 in the crank as shown inFigure 5. By applyin pressure upon the crank, the end I2'6a pressesagainst the disc I40 and carries tubular housing I36 and flanged collarI 34 inwardly and concurrently disengaging the bosses I48 from unionwithin the recesses I48, thus freeing the flanged collar I34 withrespect to the fixed collar I30, whereby the shaft I26 is free to rotatewithin the sleeve H8 independently of the train of gears keyed to thesleeve, thus enabling the shaft 50 or the shaft 84 to be manuallyrotated, depending of course upon which of the sections of the bed thatit is desired to elevate or lower.

Upon disengaging the crank from engaged position upon the pin I26, thespring I44 thrusting outwardly from the surface 901) forces the flangedcollar I34 and tubular housing I35 in the direction of the arrow C,whereby the recesses I49 again engage the bosses I48, in which positionthe assembly is again ready for power driven operation, which isnormally had through the motor driven gears I06, I08, H4 and H6. Sincethe gear H6 is keyed at M6 to the tubular sleeve H8, and since thesleeve H8 is keyed at I35 to the flanged collar I34, and since thecollar I 34 is in detachable engagement with the collar I30 which isfixedly secured to the shaft I26, rotation of the aforementionedelements of the power drive will effect rotation of the shaft I26 and ofthe shaft 50 or 84 depending of course upon which of the power units isbeing used.

The electrical circuit used to energize the motors may be described asfollows. Electrical energy flowing from a source not shown, movesthrough the lead 200 to point 202, thence through lead 204 to the leg206 of the transformer 208, the return being through lead 2I0 to point2I2, thence through the fuse 2 I4 to the lead 2 I6. The secondary of thetransformer 208 supplies power through the rectifier 2I8 for the lowvoltage circuit beginning at positive point 22I and lead 224, which leadextends to the manual switch I54 which may be thrown to either closingcontact 256 or 258, whereby the head section 44 of the bed may be raisedand lowered.

A lead 266 extends from the hot side of the switch I54 to a terminalpost 262 upon the manual switch 264 which may be thrown to close eithercontact 266 or 268, dependin upon whether it is desired to raise orlower the bed sections 58 and 60.

Upon moving the switch I54 to contact 256, electrical energy will flowthrough the lead 210, thence through the closed limit switch I50, thencethrough lead 2'14 to the relay I52 which is moved to circuit closingposition and thence through lead 216 to the opposite side of therectifier 2I9. Energizing the afore-described circuit closes the relayI52 and permits energy to flow through lead 278 to contact 280, thencethrough lead 282, through the armature 284, lead 205, relay contact 288,the arm 290, relay contact 292, lead 294, to contact 265, lead 298,through the motor field 306, lead 302, relay contact 364, the arm 306,contact 308, and lead 3"), thence to contact H2, and through the fuse2I2 to the lead 2I5, thus completing the one circuit whereby the motorIl is rotated in a right hand direction to drive the shaft 50 clockwiseas indicated by the arrow D in Figure 2, thereby raising the bed section40 to a desired point of elevation, which may be arrested at anyintermediate point by opening the switch I54, but which upon failure toopen, can in no instance go beyond a predetermined maximum position forthe reason that the limit switch I50 automatically opens when thesection 44 has attained a point of maximum elevation.

To lower the bed section 44, the following circuit is energized,remembering of course that the limit switch I56 is now closed, but hasheretofore not been energized.

Upon moving the switch I54 to contact 258, energy flows through lead3l4, the closed limit switch I56, lead 3I6 to the relay 3I3, thencethrough lead 320 to contact 322 and lead 216 which is tied in with therectifier, thus moving the relay 3I6 to circuit closing position,whereby energy to the motor I3I fiows reversely therethrough, throughthe following circuit, that is from contact 252, through lead 218,contact 280. lead 282, the armature 284, lead 286, and contact 280, therelay I52 being de-energized and the circuit therethrough being open,energy now flows through 336, to closed relay contact 332, through thearm 334, contact 336, lead 338 to contact 304, thence through lead 302,the motor field 300, lead 268, contact 296, through the arm 340 tocontact 342, thence through lead 344 to the contact 308, thence throughlead 3I0 and the fuse 2 I4 to lead 2I6, whereby the circuit to reverselyoperate the motor IOI is completed.

As previously stated in connection with raising the bed section 44, thesection may be held in any desired descending position by merely openingthe manually controlled switch I54, but in no instance can power beapplied to motor after the section "24 has reached horizontal position,for at this point the limit switch IE6 is opened and the circuittherethrough is killed, even though the operator has previously failedto manually open the switch I54.

A description of the circuits energized to raise and lower the footsections 58 and 60 through the agency of the motor I00 would berepetitious of the previously described circuit used to service themotor I6I, excepting to state that beginning at contact 280, energyflows through the lead 350 to the armature 352 of motor I00, thereafterenergy flows through a circuit which is duplicative of theafore-described circuit, upon closing the manually controlled switch252, which is energized through lead 260, which of course energizes therelays 354 and 356 whereby power flows therethrough to the motor I00.

The preceding description of the construction and operation of theinvention is believed to be inclusive of all essential featuresconcerned therewith, and from which it will appear that I have conceiveda means whereby power may be used to raise and lower the movableelements of a hospital bed easily, quickly and with a degree offlexibility that has heretofore been quite impossible, and whereby a bedridden patient may serve his own interest with respect to bedadjustments without calling for assistance as has been the caseheretofore.

I claim:

1. In a hospital type bed having bed-spring sections normally adapted tobe actuated to and from an elevated position by an electric powersource, in combination, clutch means to disconnect said power sourcefrom actuation of said bed, said clutch means comprising a collarfixedly secured upon a driven shaft, a sleeve upon said shaft and intrain with said power source, a second collar, said second collar beingslidable upon and rotatable with said sleeve and being normally indisengageable union with the other of said collars, and a tubular sleeveto transmit pressure axially of said shaft whereby said second mentionedcollar is disengaged from said first mentioned collar whereby uponapplication of longitudinally directed pressure upon said tubular sleeveand manual rotative effort to said shaft, said shaft is rotatableclock-wise and counter clock-wise independently of said power source toeffect actuation of said bed.

2. In a manual release from a power drive for hospital beds wherebyelements of said bed may be actuated independently of said power drive,said manual release being cooperative with a r0- tatable shaft andsleeve upon said shaft, the sleeve being in train with said power drive,a flanged collar upon said sleeve in slidable splined relationshiptherewith whereby limited lineal movement thereof may be had, saidcollar being formed with recesses in a face thereof, an aperturedtubular housing centered upon said shaft and secured to said flangedcollar and being adapted to independent lineal movement with respect tothe shaft, a second collar, said second collar being fixed to said shaftfor unitary movement therewith and being formed with lugs upon a facethereof, an extensile spring pressing upon said flanged recessed collarwhereby the collar is forced into union with said second mentionedcollar and the lugs thereon, said tubular housing providing a surfacewhereby upon application of a longitudinally directed pressure thereto,said tubular housing and entrained flanged collar are disjoined from thelugs on said second collar whereby said shaft is disjoined with respectto said power drive.

3. In a hospital bed having a spring formed of separate although relatedsections, certain of which sections are adapted and arranged to be movedto and from a horizontal position by preselected power source rotationof a shaft connected to levers thereon, the combination of a clutchingdevice adapted to convert said shaft to and from crank-driven manualrotation with respect to other power actuation thereof for raising andlowering said bed sections, said clutching device being pendentlysupported by bed structure and including a freely rotatable tubularsleeve on said shaft in train with said other power source, a collarrotatable with said shaft having lugs thereon, a second collar, saidsecond collar being slidable on splines on the sleeve and havingrecesses therein to normally receive said lugs, in mated uniontherewith, and resilient means arranged to maintain such union, a thirdcollar, said last mentioned collar being inwardly slidable upon theshaft in response to pressure applied to the outer face thereof, andtubular means connecting the first and third mentioned collars forunitary movement thereof whereby upon inward application of pressureupon said third collar said lugs are disengaged from said recesses, acrank, a pin extending through said shaft adapted to be engaged by andto hold said crank on said shaft for rotation thereof, said crank beingso constructed and arranged as to be slidable longitudinally of and uponsaid shaft in face pressure contact with said third collar fordisengaging said shaft and sleeve and whereby said shaft and sleeve maybe retained in disengaged position.

4. The structure set forth in claim 3, said crank being formed withtubular end having a wall formed with a reversely directed slot thereinadapted and arranged to engage said pin and shaft and third collarwhereby said shaft and sleeve may be disengaged and whereby said shaftand sleeve are retained in such disengaged position for freeing theshaft for clockwise and counter-clockwise rotation.

5. In a hospital bed having a spring formed of separate although relatedsections certain of which sections are adapted and arranged to be movedto and from a horizontal position by preselected power source rotationof a shaft connected to levers thereon, the combination of a clutchingdevice adapted to convert said shaft to and from crank-driven manualrotation with respect to other power actuation for raising and loweringsaid bed sections, said clutching device including a sleeve upon saidshaft normally adapted to said other power driven rotation, a secondsleeve, a first, a second, and a third collar, said first mentionedcollar being in slidable union with said first mentioned sleeve andhaving a clutch face thereon, said second collar being fixedly pinnedupon said shaft and having a clutch face engageable with the otherclutch face, said third mentioned collar being centered upon said shaftand being slidable longitudinally thereof, said second sleeve beingarranged to relate initial movement of either of said first or thirdmentioned collar to the other thereof and spring means unilaterallyoperable to cause engagement of said clutch faces, a pin on said shaft,and a crank provided with a tubular end adapted and arranged to receivethe shaft and pin in relative longitudinal movement, said crank in itstubular end having a reversely directed slot in a wall thereof arrangedto clear said pin upon first 0 Number applying an indirected horizontalpressure displacing said third collar and in sequence to engage said pinafter partial rotation of the crank and release thereof whereby saidthird mentioned collar is held in displaced position, the relationshipbetween said crank and pin being such as to maintain displacement of thethird mentioned collar and entrained first, mentioned collar to effectcontinuing disconnection of said clutch faces and free rotation of saidshaft whereby the bed-spring sections may be selectively moved to andfrom a horizontal position upon rotation of said crank.

6. In a hospital bed having bed-spring sections adapted and arranged tobe screw-shaft actuated to and from horizontal position by a motordriven unit pendently supported by said bed so as to be self-alignablewith respect to any bed-spring position removed from the horizontal, thecombination with said motor driven unit of means adapted to permit ofselective manual actuation of the bed-spring sections, said meanscomprising a rotatable sleeve positioned on said screw shaft and inconstant rotatable relationship with said motor drive unit, a collar onsaid sleeve and a pair of collars on said shaft, co-operable clutchingmeans on said first mentioned collar and on one of the collars of thepair thereof, a second sleeve, said second sleeve joining the firstmentioned of said collars and the other of the collars of the pairthereof whereby unitary movement thereof is had, a crank, said crankhaving a tubular end adapted and arranged for inward slidable movementon said shaft so as to apply an inwardly directed pressure upon one ofthe collars of the pair thereof so as to effect displacement of thefirst mentioned collar and disjoining of said clutching means, a pin onsaid shaft, said crank being so constructed as to be lockable upon saidpin upon partial rotation of the crank and release thereof subsequent tothe initial application of inward pressure upon the crank whereby saidclutching means are held disjoined to enable free rotation of the shaftin raising and low ering said bed-spring sections.

ARCHIE LOGAN BURKI-IART. I

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Baush Jan. 5, 1892 Taylor Apr. 25, 1911Sabatino Mar. 12, 1912 Terry Mar. 4, 1913 Wood Mar. 21, 1922 Smith Dec.20, 1938 Banker Jan. 7, 1941 Freund Apr. 14, 1942 Davis Dec. 14, 1943Drexler et al. Mar. 14, 1944 Buttikofer May 23, 1944 D-rexler Mar. 26,1946 Jeppesen et al. Aug. 19, 1947

